mirror of
https://github.com/Waujito/youtubeUnblock.git
synced 2024-12-22 06:15:31 +00:00
313 lines
6.8 KiB
C
313 lines
6.8 KiB
C
#include "utils.h"
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#include "logging.h"
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#ifdef KERNEL_SPACE
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#include <linux/ip.h>
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#else
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#include <stdlib.h>
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#include <libnetfilter_queue/libnetfilter_queue_ipv4.h>
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#include <libnetfilter_queue/libnetfilter_queue_tcp.h>
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#endif
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void tcp4_set_checksum(struct tcphdr *tcph, struct iphdr *iph)
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{
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#ifdef KERNEL_SPACE
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uint32_t tcp_packet_len = ntohs(iph->tot_len) - (iph->ihl << 2);
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tcph->check = 0;
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tcph->check = csum_tcpudp_magic(
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iph->saddr, iph->daddr, tcp_packet_len,
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IPPROTO_TCP,
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csum_partial(tcph, tcp_packet_len, 0));
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#else
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nfq_tcp_compute_checksum_ipv4(tcph, iph);
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#endif
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}
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void ip4_set_checksum(struct iphdr *iph)
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{
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#ifdef KERNEL_SPACE
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iph->check = 0;
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iph->check = ip_fast_csum(iph, iph->ihl);
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#else
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nfq_ip_set_checksum(iph);
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#endif
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}
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int ip4_payload_split(uint8_t *pkt, uint32_t buflen,
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struct iphdr **iph, uint32_t *iph_len,
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uint8_t **payload, uint32_t *plen) {
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if (pkt == NULL || buflen < sizeof(struct iphdr)) {
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lgerror("ip4_payload_split: pkt|buflen", -EINVAL);
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return -EINVAL;
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}
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struct iphdr *hdr = (struct iphdr *)pkt;
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if (hdr->version != IPVERSION) {
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lgerror("ip4_payload_split: ipversion", -EINVAL);
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return -EINVAL;
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}
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uint32_t hdr_len = hdr->ihl * 4;
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uint32_t pktlen = ntohs(hdr->tot_len);
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if (buflen < pktlen || hdr_len > pktlen) {
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lgerror("ip4_payload_split: buflen cmp pktlen", -EINVAL);
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return -EINVAL;
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}
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if (iph)
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*iph = hdr;
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if (iph_len)
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*iph_len = hdr_len;
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if (payload)
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*payload = pkt + hdr_len;
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if (plen)
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*plen = pktlen - hdr_len;
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return 0;
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}
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int tcp4_payload_split(uint8_t *pkt, uint32_t buflen,
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struct iphdr **iph, uint32_t *iph_len,
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struct tcphdr **tcph, uint32_t *tcph_len,
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uint8_t **payload, uint32_t *plen) {
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struct iphdr *hdr;
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uint32_t hdr_len;
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struct tcphdr *thdr;
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uint32_t thdr_len;
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uint8_t *tcph_pl;
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uint32_t tcph_plen;
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if (ip4_payload_split(pkt, buflen, &hdr, &hdr_len,
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&tcph_pl, &tcph_plen)){
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return -EINVAL;
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}
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if (
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hdr->protocol != IPPROTO_TCP ||
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tcph_plen < sizeof(struct tcphdr)) {
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return -EINVAL;
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}
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thdr = (struct tcphdr *)(tcph_pl);
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thdr_len = thdr->doff * 4;
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if (thdr_len > tcph_plen) {
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return -EINVAL;
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}
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if (iph) *iph = hdr;
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if (iph_len) *iph_len = hdr_len;
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if (tcph) *tcph = thdr;
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if (tcph_len) *tcph_len = thdr_len;
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if (payload) *payload = tcph_pl + thdr_len;
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if (plen) *plen = tcph_plen - thdr_len;
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return 0;
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}
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int udp4_payload_split(uint8_t *pkt, uint32_t buflen,
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struct iphdr **iph, uint32_t *iph_len,
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struct udphdr **udph,
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uint8_t **payload, uint32_t *plen) {
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struct iphdr *hdr;
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uint32_t hdr_len;
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struct udphdr *uhdr;
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uint32_t uhdr_len;
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uint8_t *ip_ph;
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uint32_t ip_phlen;
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if (ip4_payload_split(pkt, buflen, &hdr, &hdr_len,
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&ip_ph, &ip_phlen)){
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return -EINVAL;
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}
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if (
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hdr->protocol != IPPROTO_UDP ||
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ip_phlen < sizeof(struct udphdr)) {
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return -EINVAL;
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}
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uhdr = (struct udphdr *)(ip_ph);
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if (uhdr->len != 0 && ntohs(uhdr->len) != ip_phlen) {
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return -EINVAL;
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}
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if (iph) *iph = hdr;
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if (iph_len) *iph_len = hdr_len;
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if (udph) *udph = uhdr;
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if (payload) *payload = ip_ph + sizeof(struct udphdr);
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if (plen) *plen = ip_phlen - sizeof(struct udphdr);
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return 0;
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}
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// split packet to two ipv4 fragments.
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int ip4_frag(const uint8_t *pkt, uint32_t buflen, uint32_t payload_offset,
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uint8_t *frag1, uint32_t *f1len,
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uint8_t *frag2, uint32_t *f2len) {
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struct iphdr *hdr;
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const uint8_t *payload;
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uint32_t plen;
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uint32_t hdr_len;
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int ret;
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if (!frag1 || !f1len || !frag2 || !f2len)
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return -EINVAL;
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if ((ret = ip4_payload_split(
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(uint8_t *)pkt, buflen,
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&hdr, &hdr_len, (uint8_t **)&payload, &plen)) < 0) {
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lgerror("ipv4_frag: TCP Header extract error", ret);
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return -EINVAL;
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}
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if (plen <= payload_offset) {
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return -EINVAL;
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}
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if (payload_offset & ((1 << 3) - 1)) {
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lgerror("ipv4_frag: Payload offset MUST be a multiply of 8!", -EINVAL);
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return -EINVAL;
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}
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uint32_t f1_plen = payload_offset;
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uint32_t f1_dlen = f1_plen + hdr_len;
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uint32_t f2_plen = plen - payload_offset;
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uint32_t f2_dlen = f2_plen + hdr_len;
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if (*f1len < f1_dlen || *f2len < f2_dlen) {
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return -ENOMEM;
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}
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*f1len = f1_dlen;
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*f2len = f2_dlen;
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memcpy(frag1, hdr, hdr_len);
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memcpy(frag2, hdr, hdr_len);
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memcpy(frag1 + hdr_len, payload, f1_plen);
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memcpy(frag2 + hdr_len, payload + payload_offset, f2_plen);
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struct iphdr *f1_hdr = (void *)frag1;
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struct iphdr *f2_hdr = (void *)frag2;
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uint16_t f1_frag_off = ntohs(f1_hdr->frag_off);
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uint16_t f2_frag_off = ntohs(f2_hdr->frag_off);
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f1_frag_off &= IP_OFFMASK;
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f1_frag_off |= IP_MF;
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if ((f2_frag_off & ~IP_OFFMASK) == IP_MF) {
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f2_frag_off &= IP_OFFMASK;
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f2_frag_off |= IP_MF;
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} else {
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f2_frag_off &= IP_OFFMASK;
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}
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f2_frag_off += (uint16_t)payload_offset / 8;
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f1_hdr->frag_off = htons(f1_frag_off);
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f1_hdr->tot_len = htons(f1_dlen);
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f2_hdr->frag_off = htons(f2_frag_off);
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f2_hdr->tot_len = htons(f2_dlen);
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lgdebugmsg("Packet split in portion %u %u", f1_plen, f2_plen);
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ip4_set_checksum(f1_hdr);
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ip4_set_checksum(f2_hdr);
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return 0;
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}
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// split packet to two tcp-on-ipv4 segments.
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int tcp4_frag(const uint8_t *pkt, uint32_t buflen, uint32_t payload_offset,
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uint8_t *seg1, uint32_t *s1len,
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uint8_t *seg2, uint32_t *s2len) {
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struct iphdr *hdr;
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uint32_t hdr_len;
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struct tcphdr *tcph;
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uint32_t tcph_len;
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uint32_t plen;
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const uint8_t *payload;
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int ret;
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if (!seg1 || !s1len || !seg2 || !s2len)
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return -EINVAL;
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if ((ret = tcp4_payload_split((uint8_t *)pkt, buflen,
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&hdr, &hdr_len,
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&tcph, &tcph_len,
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(uint8_t **)&payload, &plen)) < 0) {
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lgerror("tcp4_frag: tcp4_payload_split", ret);
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return -EINVAL;
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}
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if (
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ntohs(hdr->frag_off) & IP_MF ||
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ntohs(hdr->frag_off) & IP_OFFMASK) {
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lgdebugmsg("tcp4_frag: frag value: %d",
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ntohs(hdr->frag_off));
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lgerror("tcp4_frag: ip fragmentation is set", -EINVAL);
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return -EINVAL;
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}
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if (plen <= payload_offset) {
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return -EINVAL;
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}
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uint32_t s1_plen = payload_offset;
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uint32_t s1_dlen = s1_plen + hdr_len + tcph_len;
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uint32_t s2_plen = plen - payload_offset;
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uint32_t s2_dlen = s2_plen + hdr_len + tcph_len;
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if (*s1len < s1_dlen || *s2len < s2_dlen)
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return -ENOMEM;
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*s1len = s1_dlen;
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*s2len = s2_dlen;
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memcpy(seg1, hdr, hdr_len);
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memcpy(seg2, hdr, hdr_len);
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memcpy(seg1 + hdr_len, tcph, tcph_len);
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memcpy(seg2 + hdr_len, tcph, tcph_len);
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memcpy(seg1 + hdr_len + tcph_len, payload, s1_plen);
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memcpy(seg2 + hdr_len + tcph_len, payload + payload_offset, s2_plen);
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struct iphdr *s1_hdr = (void *)seg1;
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struct iphdr *s2_hdr = (void *)seg2;
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struct tcphdr *s1_tcph = (void *)(seg1 + hdr_len);
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struct tcphdr *s2_tcph = (void *)(seg2 + hdr_len);
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s1_hdr->tot_len = htons(s1_dlen);
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s2_hdr->tot_len = htons(s2_dlen);
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s2_tcph->seq = htonl(ntohl(s2_tcph->seq) + payload_offset);
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lgdebugmsg("Packet split in portion %u %u", s1_plen, s2_plen);
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tcp4_set_checksum(s1_tcph, s1_hdr);
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tcp4_set_checksum(s2_tcph, s2_hdr);
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return 0;
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}
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